An enhanced coagulation using ferric chloride and poly-ferric chloride coagulant assisted by polyamidine: Performance and mechanisms

The deterioration of water caused by industrial production is a thorny problem. Solving the problem co-gently through innovative coagulationstrategies has been recognized of important practical significance. In this work, a simple enhanced coagulation by using ferric chloride (FC) and poly-ferric chloride (PFC) cou-pled with polyamidine (PA) were tried to remove the toxic organics. The results shown that PA addition could obviously enhance coagulation performances of the iron-based coagulants. The synergic coagulation process and mechanism were studied and discussed in detail based on the coagulation behaviors, flocs properties, removal efficiency and zeta potentials. FC and PFC remove organics mainly through charge neutralization and adsorption-bridging, resulting in a good purification performance. While PA with a higher charge density showed better purification performance due to enhanced charge neutralization. It is worth mentioning that the addition of PA could make the coagulants adapt to a wider pH range, and remove the toxic organics more effectively. That is to say, the practical adaptability of the coagulant was enhanced. This work thus provides a simple strategy to effectively purify wastewater and further improve the water safety.(c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.